On Facebook, when you receive a request from someone who you see has several mutual friends, but you know that you have never met them and don't really want to accept their friend request, but you do anyway to avoid looking like an asshole/bitch, this is considered a courtesy accept.

I had to courtesy accept her friend request so I wouldn't look like a dick. She's friends with Tina, so I don't want her to tell Tina I'm a dick, I can't be havin that shizz yo.